Point, but I find rules-light systems to be inviting more arguments and bickering than they prevent.
Close? Sure. The character who took disadvantages will have an edge, but the disadvantages will be a burden. If he goes crazy with them they will also be a burden for the whole group (which is why the Basic Set urges GMs to set a hard limit on disadvantages).
The real "munchkin exploit" in GURPS is buying down attribute levels (which are counted as disadvantages), which is closer to just taking 8s on irrelevant stats in a point buy game. You'll see people on the Steve Jackson Games forums talk about IQ! or HT!